This invention relates to electrical connection devices and, more particularly, to a connection device having movable, magnetic balls coated with a fusible material.
Centralization of common telephone switching equipment in a single location, such as a central switching office, produced the need to provide flexibility of interconnection between outside cable plant and central office equipment. A main distributing frame answers this need by terminating outside plant cable pairs on one side of the frame and inside plant pairs from the central office equipment on the other side of the frame. Basically, a main distributing frame provides a means whereby outside plant cable may be cross-connected to a selected central office circuit by placing a cross-connection, or jumper, wire pair between the appropriate terminal strip appearances on either side of the main distributing frame.
While the main frame functions satisfactorily so long as there is capacity for the addition of new connections, there is also a continuing need to change and rearrange existing cross-connections. This results in high labor costs because all cross-connection changes must be done manually. Also in many cases existing main distributing frames have become completely filled with cross-connection wire pairs making it almost impossible to remove an obsolete cross-connection before placing a new cross-connection. Some main distributing frames have become so congested with active and dead cross-connection wire pairs that new cross-connections cannot be made, and such main distributing frames have had to be abandoned and replaced by new main distributing frames. The installation of new frames requires replacement and termination of cables from outside plant and central office equipment along with replacement of necessary cross-connections.
A main distributing frame having manually wired cross-connections is in essence a large passive switch. A passive switch is a mechanism for making a connection between two leads without an automatic actuator. Such type of switch has a low initial cost but a high operating cost because it requires extensive manual labor during operation. On the other hand, presently known electromechanical or electronic switches which might be used in a main distributing frame can be automated but are too expensive for normal main distributing frame applications. Thus, a need exists for new concepts in providing the cross-connections in main distributing frames in telephone central offices.
U.S. Pat. No. 3,838,317, issued on Sept. 24, 1974 and assigned to the assignee of this invention, discloses a cross-connect switch which may be used to provide cross-examinations in an automated main distributing frame. Although the disclosed switch offers many advantages of existing crosspoint switches, its electrical cross-connections depend upon purely mechanical forces to establish and maintain the connections. This type of electrical connection is susceptible to degradation caused by vibration and corrosion.
Therefore, it is an object to provide another connection device for use in an automated main distributing frame.
Another object is to provide a connection device which is a relatively low cost device.
Yet another object is to provide a connection device which establishes a permanent, fused, electrical connection which will not be degraded by vibration or corrosion causing agents present in a central office.
These and other objects are realized in an illustrative embodiment thereof in which a connection device has first and second conductors separated by an insulator having an aperture between the two conductors. A plurality of magnetic balls is contained within the aperture by the two conductors. Each conductor and each ball is coated with a material having a melting point above 85.degree. F. An attracting magnetic force applied to the balls aligns and holds them in contact between the two conductors while a heat source applies sufficient heat to melt the material on the balls and conductors. Upon cooling, the material solidifies fusing the balls and the conductors together into a permanent connection.
A feature of the invention is the fusible material on the balls and the conductors.
Another feature is a means for heating the material.
A further feature is that the material fuses the balls and the conductors together into a connection between the two conductors.
Yet another feature is an arrangement for breaking the fused connection.